With the rapid market expansion of notebook computers, mobile phones, electric cars, and the like, secondary batteries having a high energy density have been demanded. Means for obtaining a secondary battery having a high energy density includes a method using a negative electrode material having a high capacity, and a method using a non-aqueous electrolyte solution which is excellent in stability.
Patent Literature 1 discloses a negative electrode for a secondary battery, provided with an active material layer comprising carbon material particles capable of intercalating and deintercalating lithium ions, metal particles capable of forming an alloy with lithium, and oxide particles capable of intercalating and deintercalating lithium ions. Patent Literature 2 discloses a negative electrode material for a secondary battery, obtained by coating with carbon the surface of particles having a structure in which silicon fine crystals are dispersed in a silicon compound.